Tool turret

ABSTRACT

A tool turret having a housing ( 1 ), a turret head ( 2 ) which can be rotated relative to the housing ( 1 ) by means of a drive, two toothed rims ( 4, 9″ ) which are arranged coaxially with respect to the rotational axis of the turret head ( 2 ) and of which the one ( 4 ) is connected fixedly to the turret head ( 2 ) so as to rotate with it and the other ( 9″ ) is connected fixedly to the housing ( 1 ) so as to rotate with it, a locking part ( 24 ) which can be moved axially relative to the housing ( 1 ) and to the turret head ( 2 ), with the toothing system ( 24′ ) which is oriented towards the two toothed rims ( 4, 9″ ) and, in its locked position, is in engagement with the latter as a positively locking connection, and a pressure fluid control device for actuating the movement of the locking part ( 24 ), is characterized in that, in the locked state, an additional frictionally locking connection ( 73 ) is established between the housing ( 1 ) and the turret head ( 2 ) by means of a frictionally locking device ( 67 ), in addition to the positively locking connection ( 4, 9″, 24′ ). 
     Ein Werkzeugrevolver mit einem Gehäuse ( 1 ), einem relativ zum Gehäuse ( 1 ) mittels eines Antriebes drehbaren Revolverkopf ( 2 ), zwei koaxial zur Drehachse des Revolverkopfes ( 2 ) angeordneten Zahnkränzen ( 4, 9″ ), von denen der eine ( 4 ) drehfest mit dem Revolverkopf ( 2 ) und der andere ( 9″ ) drehfest mit dem Gehäuse ( 1 ) verbunden ist, einem relativ zum Gehäuse ( 1 ) und zum Revolverkopf ( 2 ) axial bewegbaren Verriegelungsteil ( 24 ) mit einer auf die beiden Zahnkränze ( 4, 9″ ) ausgerichteten und in seiner Verriegelungsstellung mit diesen in Eingriff als formschlüssige Verbindung stehenden Verzahnung ( 24′ ) und einer 
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The invention relates to a tool turret having a housing, a turret head which can be rotated relative to the housing by means of a drive, two toothed rims which are arranged coaxial to the rotational axis of the turret head, and of which the one is connected fixedly to the turret head and the other is connected fixedly to the housing, a locking part which can be moved axially relative to the housing and to the turret head, with a tooth system which is oriented towards the two toothed rims and, in its locked position, is in engagement with the latter as a form-fitting connection, and with a pressure fluid control device for activating the movement of the locking part.

Tool turrets of this kind are state of the art, see document DE 41 16 774 C1. The operational reliability of machine tools equipped with such tool turrets is to a large degree dependent on the functional reliability of the locking of the turret head. The reliability of the tooth system engagement is in particular inadequate when limited activation force is available for the movement of the locking part, which is formed as a pressure piston, because for example for a large effective piston surface of the locking part, as is required for a pneumatic activation, adequate space is not available. In order to ensure reliable locking in spite of low activation force with a limited effective piston surface, the above-mentioned known solution envisages a special tooth form of the tooth system, with a small flank angle and a trapezoidal cross section form of the teeth. This solution is unsatisfactory in particular because the envisaged tooth form threatens the reliability of the tooth system engagement due to possible head-to-head contact.

Given this prior art, the problem addressed by the invention is to provide a tool turret of the type mentioned above, which is distinguished by a particularly reliable locking between the turret head and the housing.

According to the invention, this problem is solved by means of a tool turret having the features of Claim 1 in its entirety.

According to the characterizing part of Claim 1, a significant feature of the invention is that, in the locked state, an additional frictionally locking connection is established between the housing and the turret head by means of a frictionally locking device, in addition to the form-fitting connection. Because the locking engagement is additionally ensured by the simultaneously effective frictional locking, it is not necessary to realize the measures required in the prior art such as the space requirement-increasing enlargement of the piston surface of the locking part and special tooth forms of the tooth system, which may threaten the reliable tooth system engagement. In the case of low space requirement and reliably realizable shifting operations, a high level of operational reliability of the locking can thus be achieved. When the term turret head is used here, this term includes tool disks, in particular for tool turrets of machine tools for machining work.

The frictional locking device has in advantageous exemplary embodiments a chamber which can be filled with pressure fluid between the housing and the turret head, with the chamber lying outside of the possible tooth system engagement and with a pressure effective surface, which is arranged between the housing and the turret head, and which establishes the frictional locking when pressure is applied.

The arrangement can particularly advantageously be such that the chamber which can be filled with pressure fluid in the locked state likewise has pressure fluid applied to it by the pressure fluid control device. This reduces the construction costs for pressure supply channels extending in the housing by means of common supply of the locking part and the frictional locking device.

The locking part can be formed as a pressure piston, to which the pressure fluid of the pressure fluid control device can be applied on opposite surfaces. Thus both the locking engagement and the unlocking takes place in a pressure-controlled manner and in a particularly operationally reliable manner. Pressure supply channels which are separate from one another can extend in the housing for the pressure supply of the opposite surfaces of the locking part.

In particularly advantageous exemplary embodiments the housing has an outwards projecting guiding step, which is overlapped by the turret head at the edge, with the chamber extending at the point of this overlap between the housing and the turret head. When the chamber has the pressure fluid applied to it, the frictional locking between the guiding step of the housing and the turret head can be formed.

The arrangement can particularly advantageously be such that on the side of the housing, which lies opposite its tooth system, the chamber is continued by means of a boundary between the turret head and the housing, which forms an effective surface, which in the case of pressure application draws the turret head in the direction of a step surface of the guiding step, which is adjacent to the tooth system of the turret head and which forms the friction surface.

For the rotatable mounting of the turret head on the housing, on the outerlying guiding surface of the guiding step of the housing at least one bearing can be installed, along which the rotating turret head is guided, while on the free face side thereof a tool disk can be fixed, which has a plurality of tool receptacles for receiving tools for the machining work.

A further subject of the invention is a Hirth toothing device, which is envisaged in particular for a tool turret according to one of the preceding claims and which has the features of Claim 10.

The invention is explained in detail below with reference to an exemplary embodiment depicted in the drawings, in which:

FIG. 1 shows an incomplete and schematically simplified longitudinal section of a tool turret of the prior art;

FIG. 2 shows a schematically simplified and broken off partial longitudinal section, in which, of an exemplary embodiment of the tool turret according to the invention, the partial area adjacent to the locking device between the housing and the turret head is depicted;

FIG. 3 shows a depiction corresponding to FIG. 2 with a cutting plane which is rotated relative thereto; and

FIG. 4 shows an enlarged partial cutout from FIG. 3.

FIG. 1 shows the tool turret known in the prior art from document DE 41 16 774 C1, of which the following text only describes those parts which are relevant to this invention. Furthermore, reference is made to document DE 41 16 774 C1. The tool turret has a turret head 2 which is mounted rotatable in a turret housing 1, which in a known manner is provided with receptacles 3 for tool supports. On the side of the turret head 2 facing the inside of the turret housing 1 a toothed rim 4 is provided, which lies concentric to the rotational axis of the turret head 2 and forms a radial tooth system facing the inside of the turret housing 1.

The rotary drive of the turret head 2 for a rotation of the latter to one of the selectable angular positions occurs in the depicted, known tool turret not directly via a centrally arranged shaft 5, but rather via a hollow cylindrical body 6 concentrically surrounding a portion of the shaft 5, against the one face end of which the turret head 2 lies. Screws 7 connect the turret head 2 to the hollow cylindrical body 6. The annular material section of the turret head 2 supporting the toothed rim 4 is supported at its outer skin surface via a bearing 8 on a ring 9, which is connected to the turret housing 1 and which forms a radially outwards extending flange 9. By means of a second radial bearing 10, the hollow cylindrical body 6 is rotatably mounted in the turret housing 1.

The rotary drive of the hollow cylindrical body 6 occurs via a planetary gear 11 which, next to its face end facing away from the turret head 2 is rotatably mounted thereon. This planetary gear 11 cogs both with a toothed rim 12 provided on the turret housing 1 and with a sprocket 13, which has a common hub with a toothed wheel 14 arranged axially next to it. This common hub is mounted on the one hand by means of a bearing 15 on the shaft 5 and on the other hand by means of a bearing 16 in a bore of a front wall 17 of the turret housing 1. The rear end section of the shaft 5 is additionally mounted in this front wall 17 by means of a bearing 18. The toothed wheel 14 is engaged with a sprocket 19, which is fixedly arranged together with a toothed wheel 20 on an auxiliary shaft 21 arranged parallel to the shaft 5, which is mounted rotatable in the turret housing 1 and the front wall 17 by means of the bearing 32. A sprocket 22 cogs with the toothed wheel 20, which sprocket sits on the shaft of a drive motor 23, which is fixed on the turret housing 1 and on its front wall 17.

The ring 9 fixed on the turret housing 1 forms a second toothed rim 9″ in the form of a radial tooth system, the teeth of which form a radial extension of the teeth 28 of the toothed rim 4, when these are oriented towards the teeth of the second toothed rim 9″.

For the centering of the turret head 2 and its locking in the selectable angular positions, a locking part in the form of an annular piston 24 is provided, the inner skin surface of which is aligned with the inner skin surface of the toothed rim 4 and the outer skin surface of which is aligned with the outer skin surface of the second toothed rim 9″, because both toothed rims project into the annular work space 25 from the one face side thereof, in which the piston 24 is arranged in an axially displaceable manner. As FIG. 1 shows, the annular work space 25 is delimited on the inside and on the end facing away from the turret head 2 by a groove-like turned recess of the hollow cylindrical body 6 and on the outside by the inner skin surface of the turret housing 1.

The piston 24, which is provided both at its outer skin surface and at its inner skin surface with a respective annular groove for receiving a ring seal 26, has on the face side facing the toothed rim 4 and the second toothed rim 9″ a radial tooth system 24′, which is formed corresponding to the tooth systems of the two toothed rims 4 and 9″ in order that the turret head 2 can be exactly positioned in each selectable angle position and can be locked in a substantially play-free manner to the turret housing 1.

Of an exemplary embodiment of the tool turret according to the invention FIGS. 2 to 4 depict only the partial area adjacent to the locking device 5 between the housing 1 and the turret head 2, with a tool disk having receptacles for tool supports being omitted, which is mounted on a contact surface 41 at the outer ring flange 40 of the turret head 2. This turret head overlaps a guiding step 43 extending radially outwards from the housing 1, at the external circumference of which a radial bearing 8 guides the turret head 2 in its rotational movement around the housing 1.

In FIGS. 2 to 4 the locking device is shown in the unlocked position, in which the locking part in the form of the pressure piston 24 with its radial tooth system 24′ is raised from the tooth system on the toothed rim 4 of the turret head 2 and from the tooth system on the toothed rim 9″ of the housing 1. The pressure piston 24 is displaceable in an annular body 45 of the housing 1 which forms a cylinder sleeve and is sealed relative thereto by means of sealing rings 47 and 49, so that on both axially opposite sides of the piston 24 pressure chambers 51 and 53 are formed and the piston 24 can thus be displaced by means of pressure fluid supply between the unlocked position and the locked position. FIG. 2 shows the connection of a pressure supply channel 55 extending in the housing 1 to the pressure chamber 51. FIG. 3 shows the connection of a second pressure supply channel 57 to the pressure chamber 53 on the side of the piston 24 having the tooth system 24′.

The guiding step 43 of the housing 1 is sealed by means of sealing rings 59, 61 and 63 relative to the turret head 2 and by means of a sealing ring 65 relative to the annular body 45. It is thus possible to form, on the external circumference of the guiding step 43 and of the wall area connected thereto, a pressure chamber 67 which, by means of a pocket 69 and a branch pipe 71, can have pressure fluid from the supply channel 55 applied to it, when the pressure fluid control device during shifting to the locked state supplies the supply channel 55 with pressure fluid. With the depicted geometry of the guiding step 43, in which a slanted limitation surface 77 of the turret head 2 connects to the step surfaces 73 and 75 of the guiding step 43, this surface 77 forms, in the case of pressure application to the pressure chamber 67, a pressure effective surface, which at the turret head 2 generates a force component downwards (viewing direction according to the drawings), because the pressure effectiveness of the opposite step surfaces 73 and 75 is cancelled out. The turret head 2 is thus braced against the top step surface 73 of the guiding step 43, so that in the locked position under the influence of the fluid pressure a frictional locking is formed on the step surface 73 between the turret head 2 and the guiding step 43 of the housing part 1. In the thus formed additional rotation lock there is no need for additional measures to ensure the engagement of the Hirth toothing, so that no space for auxiliary devices is required and the tooth shape of the Hirth toothing can be freely selected for optimal tooth engagement in the shifting operations. 

1. A tool turret having a housing (1), a turret head (2) which can be rotated relative to the housing (1) by means of a drive, two toothed rims (4, 9″) arranged coaxial to the rotational axis of the turret head (2), of which the one (4) is connected fixedly to the turret head (2) and the other (9″) is connected fixedly to the housing (1), a locking part (24) which can be moved axially relative to the housing (1) and to the turret head (2) with a tooth system (24′) which is oriented towards the two toothed rims (4, 9″) and, in its locked position, is in engagement with the latter as a form-fitting connection, and a pressure fluid control device for activating the movement of the locking part (24), characterized in that in the locked state, an additional frictionally locking connection (73) is established between the housing (1) and the turret head (2) by means of a frictionally locking device (67), in addition to the form-fitting connection (4, 9″, 24′).
 2. The tool turret according to claim 1, characterized in that the frictionally locking device has a chamber (67) which can be filled with pressure fluid between the housing (1) and the turret head (2), which lies outside of the possible tooth system engagement and with a pressure effective surface (73), which is arranged between the housing (1) and the turret head (2) and which produces the frictional locking in the case of pressure application.
 3. The tool turret according to claim 1, characterized in that the chamber (67) which can be filled with pressure fluid in the locked state can likewise have pressure fluid applied to it from the pressure fluid control device.
 4. The tool turret according to claim 1, characterized in that the locking part is formed in the manner of a pressure piston (24), which can have the pressure fluid of the pressure fluid control device applied to it on opposite surfaces (51, 53).
 5. The tool turret according to claim 1, characterized in that for the pressure supply of the opposite surfaces (51, 53) of the locking part (24) pressure supply channels (55, 57) which are separate from one another extend in the housing (1).
 6. The tool turret according to claim 1, characterized in that the housing (1) has an outwards projecting guiding step (43), which is overlapped by the turret head (2) at the edge and in that at the point of this overlap between the housing (1) and the turret head (2) the chamber (67) extends.
 7. The tool turret according to claim 6, characterized in that on the side of the housing (1), which housing lies opposite its tooth system (9″), the chamber (67) is continued by a boundary between the turret head (2) and the housing (1), which forms an effective surface (77) which, in the case of pressure application draws the turret head (2) in the direction of a step surface (73) of the guiding step (43), which is adjacent to the tooth system (4) of the turret head (2).
 8. The tool turret according to claim 1, characterized in that on the outerlying guiding surface of the guiding step (43) of the housing (1) at least one bearing (8) is mounted, along which the rotating turret head (2) is guided.
 9. The tool turret according to claim 1, characterized in that on the free face side (41) of the turret head (2) a tool disk can be fixed with a plurality of tool receptacles for receiving tools for machining work.
 10. Hirth toothing device, in particular for a tool turret according to claim 1, with two toothed rims (4, 9″) arranged coaxially relative to one another, of which the one (9″) is fixed and the other (4) is rotatable and with an activatable locking part (24), the toothed rim (24′) of which can be connected forming a form-fitting connection to the other two toothed rims (4, 9″), characterized in that, in the locked-with-one-another state of the individual toothed rims (4, 9″, 24′), an additional frictionally locking connection (73) is established between the fixed (9″) and the rotatably guided toothed rim (4) by means of a frictionally locking device (67), in addition to the form-fitting connection. 